Vehicles may utilize fluid reservoirs to collect various fluids, such as hydraulic fluid, engine oil, or coolant. For certain vehicles, or certain applications of a vehicle, it may be desirable to pressurize the fluid reservoir above atmospheric pressure, as in a hydraulic systems to transmit power to the mechanism which produce work. The hydraulic fluid is the medium by which this power is transmitted. Furthermore, hydraulic fluid lubricates moving parts; must be stable for long periods of time; must protect the vehicle from rust and corrosion; must resist foaming and oxidation; and separate readily from air, water, and other contaminants. The hydraulic fluid must also maintain proper viscosity through a wide temperature range, and finally, and be readily available and reasonably economical to use. For proper power transmission, the viscosity of the hydraulic fluid must be maintained. Most hydraulic fluids, such as oils, tend to become thin as its temperature increases, and thickens as its temperature drops. If the viscosity is too low, the possibility of leakage past seals and from joints is increased. If the viscosity is too high, sluggish operation results and extra horsepower is required to push the hydraulic fluid through the system. Contaminants such as metallic particles, dust, and dirt not only affect the viscosity of the hydraulic fluid, but may also damage closely fitted components, and induce oxidation, thereby accelerating rust and corrosion of components. Small particles may score valves, seize pumps, clog orifices, and cause premature failure of components such that leakage can become an environmental concern. Therefore, regular maintenance is required for optimum performance. The following disclosure describes an apparatus and method which encourages the operator to perform maintenance to prevent irreparable damage to the hydraulic system of a vehicle.